Regional cerebral blood flow and oxygen consumption in human aging.

Abstract

SUMMARY The oxygen-15 continuous inhalation technique and PET were used to study the age-related changes in regional CBF and CMRO 2 . Twenty-seven patients, aged 19 to 76 years, free of any history of cerebral disease and vascular risk factors were examined in "resting state." CBF, CMRO 2 and oxygen extraction fraction (OEF) values were calculated in seven different brain structures as well as in mean gray matter. Left-right ratios were also computed for all symmetrical structures analyzed.Mean gray CBF, but not mean gray CMRO 2 , decreased linearly with age (p < 0.02). However, when younger subjects (S50 yrs) were compared to older subjects (>50 yrs), an age-related matched decrease in CBF and CMRO 2 was observed in mean gray matter (18% and 17%, p < 0.05) and in all gray matter regions analyzed, particularly in frontal, temporo-sylvian and parieto-occipital cortex. White matter CBF and CMRO 2 remained remarkably stable with advancing age.Although the possibility'of methodological artifacts was considered, we favor progressive loss of cortical neurones and/or diminished activity of those remaining to explain our findings. In addition, age-related changes in cognitive activities might also be involved. Stroke Vol 15, No 4, 1984 DESPITE NUMEROUS STUDIES, 114 the effects of aging on cerebral circulation and metabolism still remain largely unsettled. Studies on global hemispheric cerebral blood flow (CBF) and cerebral metabolic rate of oxygen (CMRO 2 ) have so far provided discrepant results: some^ concluded that CBF and CMRO 2 did not decrease with advancing age except when vascular risk factors were present, while other authors 1 2 found a parallel decline in both CBF and CMRO 2 . These discrepancies may be partially explained by different criteria for normality used. In his review on this subject, Kety 7 favored the idea that there was a rapid fall of both CBF and CMRO 2 around puberty which continued to the third decade and was followed by a more gradual decline in middle and old age.

A study of performance on tests from the CANTAB battery sensitive to frontal lobe dysfunction in a large sample of normal volunteers: Implications for theories of executive functioning and cognitive aging

“…Overall, our findings are compatible with the results of studies using a variety of neuroimaging modalities that aging is especially associated with structural, metabolic, and neurochemical changes in regions of the prefrontal cortex (Pantano et al, 1984;Riege et al, 1985;Waldemar et al, 1991), the striatum (Murphy et al, 1992;Riege et al, 1985;Rinne et al, 1993;Sawle et al, 1990;van Dyck et al, 1995), and also the temporal lobes (Arrigada et al, 1992;Loessner et al, 1995;Pantano et al, 1984;Price et al, 1991). This position is not very different from that reached by West (1996), after a comprehensive review of the available neurobiological evidence.…”

Identifying systematic errors in quantitative dynamic‐susceptibility contrast perfusion imaging by high‐resolution multi‐echo parallel EPI

“…The observed decline of the GM-WM contrast (CBV GM /CBV WM and CBF GM /CBF WM ) with age has been reported previously (1). In comparison to literature values from different modalities ( 15 O PET, Xe CT, DSC-MRI, T 1 -weighted MRI, I CT) (1,(17)(18)(19)(20)(21)(22)(23)(24)(25)(26)(27)(28), which provide CBV and CBF values listed in Table 2, roughly, a factor 4 overestimation is observed.…”

Regional Cerebral Blood Flow Using Quantitative MR Angiography

“…Many methods, including the nitrous oxide, 23 133 xenon (Xe)-single-photon emission CT (SPECT), 9,17 Xe-CT, 24 positron-emission tomography (PET) 25,26 dynamic MR, 25,27 and perfusion CT, 24 have been used to measure the regional CBF. In most studies, 9,17,[23][24][25][26][27] CBF values were reported in terms of milliliters per 100 grams of brain tissue per minute, and in some studies CBFs were determined separately for white and gray matter.…”

“…In most studies, 9,17,[23][24][25][26][27] CBF values were reported in terms of milliliters per 100 grams of brain tissue per minute, and in some studies CBFs were determined separately for white and gray matter. In a study of the effect of age on the total CBF using nongated 2D PC MRA, 5 a factor of 10.81-12.14 was used in the correlation between the total CBF (milliliters per minute) from the 2D PC MRA and the total CBF (milliliters per minute 100 grams) from the nitrous oxide, 133 Xe-SPECT, Xe-CT, and PET.…”